This series of studies focuses on the impact of folic supplements and diet on homocysteine, a risk factor for cardiovascular disease. Data from these studies are being used in support of a large scale clinical trial of homocysteine-reducing therapy as a means to prevent vascular disease. In the first study, we determined the distribution and correlates of homocysteine in fasting serum specimens from approximately 297 retired teachers. The second study was a randomized clinical trial that tested the impact of dietary patterns on homocysteine. This was done as an ancillary study to the Dietary Approaches to Stop Hypertension clinical trial. The third study was a dose response study that assessed the impact of four different doses of folic acid on homocysteine. Data collection is complete in all studies. A manuscript for study 2 has been prepared.